In WO2005080678 a method for the modification of lignocellulosic materials is disclosed. Cellulose fibres are treated with an aqueous electrolyte-containing solution of an amphoteric cellulose derivative for at least 5 minutes at a temperature of at least 50° C. The pH during the treatment is approximately 1.5-4.5 or higher than 11; or the concentration of the electrolyte is approximately 0.0001-0.05 M if the electrolyte has monovalent cations, or approximately 0.0002-0.1 M if the electrolyte has divalent cations. Further said document relates to products obtained by the above mentioned method and uses of said products for manufacturing paper with a high wet strength.
However nothing is mentioned in the above document about manufacturing of nanocellulose or similar.
In Wågberg et al (2008) the reaction between chloroacetic acid and lignocellulose fibres is described as a pre-treatment to ease delamination in a homogenizer in order to create nanocellulose or microfibrillar cellulose. However, attachment of carboxymethylcellulose polymers to the lignocellulosic fibres is not described.
Through U.S. Pat. No. 4,341,807 further a method for manufacturing a microfibrillated cellulose or nanocellulose is disclosed by using homogenization. A problem when manufacturing nanocellulose from pulp is however the clogging of the homogenizer, when the pulp is pumped through high pressure fluidizers/homogenizers. Another problem is the excessive energy consumption during homogenization, unless the pulp before refining is subjected to some type of physiochemical pretreatment. Thus there is a need for a process wherein the clogging problem and the excessive energy consumption can be alleviated and/or avoided.